Mineral oil composition



- proving Patented Feb. 28, 1950 UNITED STAT MINERAL OIL COMPOSITION EdwardA. Oberright, Woodbury, N. 1., aasignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application July 6, 1945, Serial No. 603.589 I related to compositions comprised of mineral oiland a minor proportion of, an added ingredient which will improve the oil in one or more important respects.

It is well known to those familiar with the art that mineral oil fractions refined for their various uses are in and of themselves usually deficient in one or more respects so that their practical utility is limited even in the particular field for which they have been refined. For example, mineral oil fractions refined for use as lubricants have a tendency to oxidize under conditions of use, with the formation of sludge or acidic oxidation products; also, the lighter fractions, such as gasoline and kerosene, tend to oxidize with the formation of color bodies, gum, etc. In order to prevent the formation of these products and thereby extend the useful life of the oil fraction, it is common practice to blend with such oil fraction an additive ingredient which will inhibit oxidation, such ingredients being known to the trade as oxidation inhibitors, antioxidants, sludge inhibitors, gum inhibitors, etc.

It is also the practice to add other ingredients to mineral oil fractions for the purpose of imoiliness characteristics and the wearreducing action of such mineral oils when they are used as lubricants, particularly when the oils are used for the purpose of lubricating metal surfaces which are engaged under extremely high pressures and at high rubbing speeds.

Various other ingredients have been developed for the purpose of depressing the pour point of mineral oil-fractions which have been refined for use as lubricants. Most refining treatments provide oils containing a small amount of wax which, without the added ingredient, would tend to crystallize at temperatures which render the oil impracticable for use under low temperature conditions. Additive agents have also been developed for improving the viscosity index of lubricating oil fractions. In the case of internal combustion engines, particularly those operating with high cylinder pressures, there is a decided tendency for the ordinary lubricating oil fractions to form carbonaceous deposits which cause the piston rings to become stuck fill the slots in the oil ring or rings, thus materially reducing the efliciency of the engine. Ingredients have been developed which, when added to the oil, will reduce this natural tendency of the oil to form deposits which interfere with the function of the piston rings.

It has also been discovered that certain types of recently developed hard metal alloys, such as cadmium-silver alloy bearings, are attacked by ingredients in certain types of oils, particularly 0113 of high viscosit index obtained by various methods of solvent refining. This corrosive action on such alloys has led to the development of corrosion inhibitors which may be used in solventrefined oils to protect such bearing metals against this corrosive action.

In the lighter mineral oil fractions, such as those used for fuel purposes, particularly in internal combustion engines, it has been found that the combustion characteristics of the fuel may be controlled and improved by adding minor proportions of various improving agents thereto.

The various ingredients which have beendeveloped for use in mineral oil fractions to improve such fractions in the several characteristics enumerated above are largely specific to their particular applications. Therefore, it has been the practice to add a separate ingredient for each of the improvements which is to be effected.

The present invention is predicated upon the discovery of a group or class of oil-soluble reaction products or compounds which, when added to mineral oil fractions in minor proportions, will improve the oil fractions in several respects.

The novel addition agents contemplated by this invention as multifunctional improvers for mineral oils are oil-soluble condensation products ofan aldehyde, a heterocyclic amine and a hydroxyaromatic carboxylic acid, and metal salts thereof. These condensation products, and their corresponding metal salts, are represented by the general formula:

n X5 I i. R. 000M wherein A is an aromatic nucleus, either monoor polycyclic; R- is either hydrogen or an alkyl, aralkyl, alkaryl, aryl, cycloalkyl, alkoxy or aroxy group; a represents the number of R groups attached to an aromatic nucleus A and is an integer from 0 to 3; X is a substituent such as an amino, hydroxyl,,nitro or halogen group or the like; 1) represents the number of X groups attached to an aromatic nucleus A and is either 0 or 1; M is. either hydrogen or metal; R. is either hydrogen or an alkyl, aryl, alkaryl, aralkyl or cycloalkyl group, which may contain a substituent such as hydroxyl, halogen, nitro and the like; Y is a secin their slots and which 4 ondary heterocyclic amine group, attached at a secondary (heterocyclic) nitrogen atom to the carbon atom of the t. group; and 0 represents the number of i -OY fural; etc.

groups attached to an aromatic nucleus A and is an integer from 1 to 3., It will be clear that when A is a phenyl nucleus, the sum of a, b and c will not exceed 4; and when A is a naphthalene nucelus, or other polycyclic nucleus, the sum may exceed 4.

Aldehydes contemplated by the present invention are the aliphatic aldehydes, typified by formaldehyde (such as trioxymethylene), acetaldehyde, and aldol (B-hydroxy butyraldehyde); aromatic aldehydes', representative of which is benzaldehyde; heterocyclic aldehydes, such as fur.-

The aldehyde may contain a substituent group such as hydroxyl, halogen, nitro and the like; in short, any substituent which does not take a major part in the reaction. Preference, however, is given to the aliphatic aldehydes, formaldehyde being particularly preferred.

The secondary heterocyclic amines are those characterized by attachment of a hydrogen atom to a nitrogen atom in the heterocyclic group. Representative of the amines contemplated herein are morpholine, thiomorpholine, pyrrole, pyrroline, pyrrolidine, indole, pyrazole, pyrazoline, pyrazolidine, piperidine, phenoxazine, phenthiazine and their C-substituted analogs. Substituent groups, attached to the carbon atoms of these amines, are typified by alkyl, aryl, aralkyl, alkaryl, cycloalkyl, etc. Preferred of these amines is morpholine.

Typical hydroxyaromatic carboxylic acids which may be used herein are phenol carboxylic acids, such as salicyclic acid, naphthol carboxylic acids, etc. As indicated hereabove, these acids may contain substituent groups represented by the symbols R and X in general Formula I. Particularly preferred, however, are phenol carboxylic acids and their alkyl, such as wax, substituted analogs. Preferably, such alkyl substituents are long-chain, relatively high molecular weight hydrocarbon groups having at least twenty carbon atoms. Particularly well adapted for the purpose herein described are alkyl groups derived from petroleum wax, which are predominantly straight-chain aliphatic hydrocarbons of at least twenty carbon atoms. Hydroxyaromatic carboxylic acids, and the condensation products thereof, having one or more of such groups are designated herein as wax substituted. These s-o-called wax substituents may be obtained by alkylation of a phenol or hydroxyaromatic hydrocarbon with a relatively high molecular weight aliphatic hydrocarbon or mixture of such hydrocarbons (such as petroleum wax) by any suitable procedure, such as by a Friedel-Crafts condensation of chlorinated petroleum wax with phenol, followed by earboxylation of the wax-phenol so obtained. It is to be understood, however, that short-chain or low molecular weight alkyl groups, such as amyl, may also be used.

As indicated hereinabove, metal salts are also contemplated herein. These salts may contain metal replacing only the hydroxyl hydrogen or only the carboxyl hydrogen of the condensation product, or replacing both the hydroxyl and carboxyl hydrogens thereof. Any metal may be used the oxide or hydroxide of which (in alcohol solution, if necessary) can be reacted with the intermediate condensation product, or a, salt of which can be reacted in alcohol solution with the sodium salt of the intermediate product. Among the metals contemplated for this purpose are: copper, beryllium, magnesium, calcium, strontium, barium, radium, zinc, cadmium, mercury, germawhich also removes any unreacted amine, water nium, tin, lead, vanadium. chromium, manganese,

iron. cobalt, nickel, ruthenium, palladium platinum, aluminum, antimony, arsenic, bismuth, cerium, coiumblum, gallium, gold, indium iridium, molybdenum, osmium, rubidium, selenium, tantalum, tellurim, thorium, titanium, tungsten, uranium, and zirconium. Preference is given to metals of the alkaline earth group, particularly to barium. As noted above, the metal is preferably introduced by reaction of its oxide or hydroxide with the intermediate condensation product. Where necessary, an alcohol solution of the oxide or hydroxide is used. The metal salts can also be prepared by reacting the sodium salt of the intermediate product with an alcohol solution of a salt of the desired metal, such as stannous chloride, lead acetate, thorium nitrate, titanium tetrachloride, etc.

The condensation products are believed to be formed in the manner indicated in the following equation, wherein formaldehyde, an alkyl-substituted phenol carboxylic acid, and morpholine are used as illustrations wherein R is an alkyl group.

Metal salts of the foregoing condensation product can be readily prepared by reacting the latter with a suitable metal or compound thereof.

In preparing the condensation products, the reactants may be added to each other in any order. A typical method involves adding the aldehyde to an alcohol solution of the hydroxyaromatic carboxylic acid and the heterocyclic amine. The reaction may also be carried out in the presence of other diluents or solvents such, for example, as benzol, chlorbenzene, tetrachlorethane, mineral oil, etc. In the event that mineral oil is used as a diluent, the mineral oil may be retained, rather than separated from the condensation product, thereby providing a mineral oil concentrate. Oil concentrates containing the metal salts of these condensation products are similarly obtained.

The reaction temperature may be varied considerably depending upon the time of reaction, the specific reactants used, etc. For example, the reaction can be carried out at 20-25 C. for a relatively long period of time or at the reflux temperature of the reaction mixture for a comparatively short period. By way of illustration, the reactants, in quantities such as shown in the following example, may be thoroughly mixed at 20-25 C. for several hours and the reaction completed at the reflux temperature of the reaction mixture for an additional period of several hours.

The condensation product may be waterwashed to assure complete removal of any unreacted amine and this is recommended when the amine is high 'boiling. In general, however, the procedure involves distilling off the solvent were neutral.

of reaction and water added with the reactants- (formaldehyde, for example, is generally used in a 37% aqueous solution).

The ratio of the reactants used may be varied toprovide one ,or more methylene heterocyclicin the condensation product. when equimolec ular quantities of reactants are used, it is believed that one such group is introduced. With one moi of a hydroxyaromatic carboxylic acid and two mols of amine and two mols of aldehyde, two such groups are generally introduced providing two positions, such as two positions ortho to the carboxylic acid group or one ortho and one para thereto, are not substituted with groups other than hydrogen.

Metal salts of the condensation products may be prepared by any of the well-known procedures for replacing a hydroxylor carboxyl hydrogen or both. Typical methods include: addition of an alcohol solution of a metal oxide or hydroxide to the condensation product; addition of a. metal alcoholate in alcohol solution to the condensation product; addition of an alcohol solution of a metal salt to the sodium salt of the condensation product followed by removal of the alcohol and the sodium salt formed by double decomposition; etc.

'The condensation products, and metal salts thereof, are illustrated by the following typical examples.

EXAMPLE 1 Three hundred grams of wax-phenol carboxylic acid (3-14),- a 1:2 blend in mineral oil (S. U. V. of 65 seconds at 210 F.), prepared as described in U. S. Patent No. 2,197,837, and 10.9 grams of morpholine were dissolved in benzol. To the resulting solution, 10.4 grams of a 37% aqueous solution of formaldehyde in water-Formalinwere added dropwise. The reaction mixture obtained thereby was stirred for 3 hours at room temperature (25 C.) and then refluxed for 8 hours at 80 C. The resulting reaction mixture was washed with water until the water washings Benzol was then removed from the water-washed reaction mixture by distilling the latter to a maximum temperature of 200 C. at 10 mm. pressure. The reaction product thus obtained was a 1:2 blend in mineral oil and contained 0.74% of nitrogen. This product, waxhydroxy-carboxy-benzyl morpholine (3-14), is identified herein as Product One.

EXAMPLE 2 Three hundred grams of the disodium salt of wax-phenol carboxylic acid (3-14), a 1:2 blend in mineral oil (S. U. V. of 65 seconds at 210 F.) prepared as described in U. S. Patent No. 2,197,834, and 10.2 grams of morpholine were dissolved in butyl alcohol. To the resulting alcohol solution, 9.13 grams of Formalin were added dropwise. The reaction mixture was heated at reflux, 110 C., for one hour and butyl alcohol was then distilled off at a maximum, temperature of 200 C. The alcohol-free reaction mixture was cooled to room temperature and 22.2 grams of stannous chloride in butyl alcohol was added thereto. The resulting reaction mixture was refluxed for one hour at 110 C. and butyl alcohol was removed therefrom as before. The reaction mixture was cooled, benzol was added thereto and filtered through Hi-Flo clay. The filtrate was then distilled to a maximum temperature of 175C. at 10 mm. pressure, thereby removing benzol. The reaction product, a 1:2'mineral oil blend, contained 0.65% nitrogen and 4.2% tin. Hereinafter, this product. distannous salt of wax-hydroxy-carboxy-benzyl morpholine (3-14), is referred to as Product Two.

EXAMPLE 3 One hundred grams of the dibarium salt of diamyl-phenol carboxylic acid, a 1:2 blend in mineral oil (S. U. V. of 65 seconds at 210 F.), prepared as described in U. S. Patent No. 2,197,834, and 9.2 grams of morpholine were dissolved in a butyl alcohol-benzol mixture. Formalin (8.9 grams) was added dropwise to the alcohol-benzol solution and the reaction mixture thus formed was stirred at 25 C. for 4 hours. Thereafter, the reaction mixture was refluxed at C. for 7 hours, then filtered through Hi-Flo clay and water-washed. In the water-washing operatiombarium is removed from the phenate (or hydroxyl) group. Butyl alcohol and benzol were removed from the water-washed reaction mixture by distillation to a maximum temperature of 200 C. at 10 mm. pressure. The reaction product thus obtained, a 2:3 mineral oil blend, contained 0.96% nitrogen and 3.5% barium. This product, barium carboxylate of diamyl-hydroxyl-carboxyl-benzyl morpholine, is identified herein as Product Three.

As stated hereinbefore, the reaction products contemplated by this invention and illustrated by the above examples, when added to lubricating oils in minor proportions, have been found to improve these oils in several important respects. This phenomenon is demonstrated by the following tables, which give the results of the various tests conducted to determine the effectiveness of these reaction products as addition agents for lubricating oils. The per cent of material added to the oil in the following tables is the per cent of concentrated material and does not include the oil in which the product was made.

POUR POINT DEPRESSION Tests were conducted in the conventional manner to determine the A. S. T. M. pour points of blends of these reaction products with a Mid- Contlnent solvent-refined oil of S. U. V. of 67 seconds at 210 F. as compared with the pour point of the blank oil. The results given in Table I below demonstrate the effectiveness of the reaction products contemplated herein as pour point depressants.

" VISCOSITY INDEX IMPROVEMENT A mineral oil of 41.8 seconds S. U. V. at 210 F. was tested in the conventional manner to determine the improvement in viscosity index values effected by various of the reaction products contemplated by this invention. This improvement is clearly demonstrated by the results set forth in Table 11 below.

It will be noted that viscosity index improvement is obtained when the improving agent is characterized by a carboxyl group and a wax group, and no such improvement is realized with a carboxyl group and a short-chain alkyl group. CORROSION Tasr In this test the reaction product was blended with a Pennsylvania solvent-refined oil of S. U. V. of 53 seconds at 210 F., and a section of a bearing containing a cadmium-silver alloy surface and weighing about 6 grams was added to this blend. The oil was heated to 175 C. for 22 hours while a stream of air was bubbled against the surface of the bearing. The loss in weight of the bearing during this treatment measured the amount of corrosion that had taken place. A sample of the straight oil was subjected to the same test at the same time, and the difference between the losses in weight of the two bearing sections demonstrated conclusively the effectiveness of the reaction products contemplated herein as corrosion-inhibitors.

Table III Bearing Loss, mgm. Addition Agent Pxggggt Inhibited Uninhibitcd Oil Oil Product One 0.25 4 31 OPERATION TEST To demonstrate the effectiveness of the reaction products under actual operating conditions of an automotive engine, unblended oils and improved oils, containing the reaction products, were subjected to the Lauson engine test. The tests were carried out in a single-cylinder Lauson engine operated continuously over a time interval of 16 hours with the cooling medium held at a temperature of about 212 F., and the oil temperature held at about 280 F. The engine was operated at a speed of about 1830 R. P. M. At the end of each test the oil was tested for acidity (N. N.) and viscosity. The base oil used here is a solventrefined oil having an S. U. V. of 44 seconds at 210 F.

8 It will be apparent from the foregoing test data that the condensation products. and metal salts thereof, of this invention are effective multifunctional oil improving agents.

The improved properties obtained and the degree of improvement effected may be varied with the aldehyde, heterocyclic amine, hydroxyaromatic carboxylic acid and metal used in their preparation and present in the condensation product. As indicated above by viscosity index test data, improvement is obtained when the characterizing agent contains a carboxylic acid group and a long-chain aliphatic hydrocarbon group, such as wax, and no such improvement is realized with a product containing a short-chain aliphatic hydrocarbon group in combination with a carboxylic acid group.

The amount of improving agent used varies with the mineral oil fraction with which it is blended and with the properties desired in'the final oil composition. These condensation products may be added to mineral oil in amounts of from about 0.01% to about 10%, but amounts of (Ll-5% generally provide satisfactory improvement.

It is to be understood that although I have described certain preferred procedures which may be followed in the preparation of the novel reaction products contemplated herein as multifunctional addition agents for mineral oils and have indicated representative reactants for use in their preparation, such procedures and reactants are merely illustrative and the invention is not to be considered as limited thereto or thereby but includes within its scope such changes and modifications as fairly come within the spirit of the appended claims.

I claim:

1. An improved mineral oil containing a minor proportion of paraffin wax-hydroxy-carboxybenzyl morpholine in which the morpholine group is attached at the secondary nitrogen atom thereof to the CH2 group of the benzyl radical.

2. An improved mineral oil containing a minor proportion of the distannous salt of paraflin wax hydroxy carboxy benzyl morpholine in which the morpholine group is attached at the secondary nitrogen atom thereof to the CH: group of the benzyl radical.

3. An improved mineral oil containing a minor proportion of the barium carboxylate of diamyl hydroxyl carboxyl-benzyl morpholine in which the morpholine group is attached at the secondary nitrogen atom thereof to the -CHz group of the benzyl radical.

' 4. An improved mineral oil containing a minor proportion of an oil soluble condensation prodnot represented by the general formula:

1 6M in 5 attached to an aromatic nucleus A, and is an integer from 0 to 3; M is selected from the group consisting of hydrogen and a polyvalent metal; R is selected from the group consisting of hydrogen and alkyl; Y is a morpholine group attached at a secondary nitrogen atom thereof to the carbon atom of the group; and c repreaents the number of groups attached to the aromatic nucleus A and 10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name 4 Date 

4. AN IMPROVED MINERAL OIL CONTAINING A MINOR PROPORTION OF AN OIL SOLUBLE CONDENSATION PRODUCT REPRESENTED BY THE GENERAL FORMULA: 